1. Field of the Invention
The present invention relates to a flow control valve, and more specifically to a multi port diverter valve used in fluid processing operations.
2. Description of the Prior Art
There is a wide variety of valves in the prior art that are used to divert the flow of fluids. Many of these valves are complex in structure and operation or have many moving parts. U.S. Pat. Nos. 3,613,731, 3,867,960, 4,112,974, 4,286,624 and 4,573,497 are typical in this regard. Such valves can be relatively expensive to produce and maintain. Other valves which are less complex, such as those which have reciprocating stems, are subject to accelerated wear because of the metal to metal contact between stem and sleeve. Repeated use causes the parts of valves of this type to become worn, leaky and otherwise inefficient. Valves having specially contoured surfaces are particularly prone to leakage after some degree of wear because of the close tolerances between the various parts. Typical valves having reciprocating stems are described in U.S. Pat. Nos. 3,183,933, 3,411,538 and 3,521,673. While these types of valves require less frequence maintenance, the configuration of the internal moving parts calls for replacement of their entire valve stems and related parts during maintenance activities. Such valves are subject to continued inefficient operation even after maintenance is completed if the valve ports and passages are not carefully aligned or part tolerances are improper. Thus, the proper performance of maintenance on valves of this type can require considerable equipment down time. Moreover, relatively complex control systems are often required to automate such valves, which in turn increases the maintenance costs.
There is a clearly defined need for a diverter valve which is economic, efficient and requires little maintenance. There is also a need for a diverter valve which requires replacement of a minimum number of parts during routine maintenance, has a positive shut off of leakage between the operating sides of the valve and which is readily automated.